Add API for making monitor label via wayland protocol

Author: leolost2605

protocol/pantheon-desktop-shell-v1.xml

@@ -119,6 +119,15 @@
       </description>
     </request>
 
+    <request name="make_monitor_label">
+      <description summary="makes the surface a monitor label for the given monitor">
+        Request to make the surface a monitor label for the given monitor. The surface will be placed
+        in the top left corner of the monitor and will be kept above other surfaces.
+      </description>
+
+      <arg name="monitor_index" type="int" summary="the index of the monitor this surface should label"/>
+    </request>
+
     <request name="focus">
       <description summary="request keyboard focus">
         Request keyboard focus, taking it away from any other window.

protocol/pantheon-desktop-shell.vapi

@@ -57,6 +57,7 @@ namespace Pantheon.Desktop {
         public Destroy destroy;
         public SetKeepAbove set_keep_above;
         public MakeCentered make_centered;
+        public MakeMonitorLabel make_monitor_label;
         public Focus focus;
     }
 
@@ -79,5 +80,7 @@ namespace Pantheon.Desktop {
     [CCode (has_target = false, has_typedef = false)]
     public delegate void MakeCentered (Wl.Client client, Wl.Resource resource);
     [CCode (has_target = false, has_typedef = false)]
+    public delegate void MakeMonitorLabel (Wl.Client client, Wl.Resource resource, int monitor_index);
+    [CCode (has_target = false, has_typedef = false)]
     public delegate void Destroy (Wl.Client client, Wl.Resource resource);
 }

src/PantheonShell.vala

@@ -49,6 +49,7 @@ namespace Gala {
             destroy_extended_behavior_surface,
             set_keep_above,
             make_centered,
+            make_monitor_label,
             focus_extended_behavior,
         };
 
@@ -322,6 +323,21 @@ namespace Gala {
         ShellClientsManager.get_instance ().make_centered (window);
     }
 
+    internal static void make_monitor_label (Wl.Client client, Wl.Resource resource, int monitor_index) {
+        unowned ExtendedBehaviorSurface? eb_surface = resource.get_user_data<ExtendedBehaviorSurface> ();
+        if (eb_surface.wayland_surface == null) {
+            return;
+        }
+
+        Meta.Window? window;
+        eb_surface.wayland_surface.get ("window", out window, null);
+        if (window == null) {
+            return;
+        }
+
+        ShellClientsManager.get_instance ().make_monitor_label (window, monitor_index);
+    }
+
     internal static void destroy_panel_surface (Wl.Client client, Wl.Resource resource) {
         resource.destroy ();
     }

src/ShellClients/ShellClientsManager.vala

@@ -192,6 +192,18 @@ public class Gala.ShellClientsManager : Object, GestureTarget {
         window.unmanaging.connect_after ((_window) => positioned_windows.remove (_window));
     }
 
+    public void make_monitor_label (Meta.Window window, int monitor_index) requires (!is_itself_positioned (window)) {
+        if (monitor_index < 0 || monitor_index > wm.get_display ().get_n_monitors ()) {
+            warning ("Invalid monitor index provided: %d", monitor_index);
+            return;
+        }
+
+        positioned_windows[window] = new ShellWindow (window, MONITOR_LABEL, monitor_index);
+
+        // connect_after so we make sure that any queued move is unqueued
+        window.unmanaging.connect_after ((_window) => positioned_windows.remove (_window));
+    }
+
     public override void propagate (UpdateType update_type, GestureAction action, double progress) {
         foreach (var window in positioned_windows.get_values ()) {
             window.propagate (update_type, action, progress);